The present invention relates to a one-piece rear hub shell for bicycle wheels that consists of a tube with heads on it at the sides and that have perforations to accommodate wheel spokes.
Hub shells of this type now consist in general of metal. Some in particular are made in several parts out of steel and some in one piece out of aluminum. Both types are expensive to manufacture partly because of complicated assembly operations and partly because of the high cost of aluminum.
A multipart hub shell in which the tube and adjacent areas are made in one piece out of plastic and function as an external accommodation for the bearing while the flanged heads are again made out of metal is also known, with the extensive involvement of metal parts and the requisite assembly operations again accounting for high manufacturing costs.
None of the known hub shells involve any problems in attaching the drive mechanism, specifically the wheels for the chain drive, each on at least one side of the shell and on its own hub head, because a metal component is available there in all known designs that provides sufficient strength for the fine threading that chain wheels are conventionally supplied with to transmit the drive forces.